System and method for an uplink control signal in wireless communication systems

ABSTRACT

A user equipment is capable of receiving communications from a cell including at least one base station. The user equipment includes a receiver configured to receive from the base station both a cell specific radio resource control (RRC) configuration comprising a cell specific resource offset parameter for a PUCCH HARQ-ACK, and a UE specific RRC configuration comprising a UE specific RS base sequence parameter and an UE specific resource offset parameter for the PUCCH HARQ-ACK.

CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY

The present application is related to U.S. Provisional Patent No.61/498,989, filed Jun. 20, 2011, entitled “METHODS AND APPARATUS ONUPLINK REFERENCE SIGNALS”. Provisional Patent No. 61/498,989 is assignedto the assignee of the present application and is hereby incorporated byreference into the present application as if fully set forth herein. Thepresent application hereby claims priority under 35 U.S.C. §119(e) toU.S. Provisional Patent No. 61/498,989.

TECHNICAL FIELD OF THE INVENTION

The present application relates generally to wireless communicationsand, more specifically, to a system and method for uplinkacknowledgement transmissions.

BACKGROUND OF THE INVENTION

Modern communications demand higher data rates and performance. Multipleinput, multiple output (MIMO) antenna systems, also known asmultiple-element antenna (MEA) systems, achieve greater spectralefficiency for allocated radio frequency (RF) channel bandwidths byutilizing space or antenna diversity at both the transmitter and thereceiver, or in other cases, the transceiver.

In MIMO systems, each of a plurality of data streams is individuallymapped and modulated before being precoded and transmitted by differentphysical antennas or effective antennas. The combined data streams arethen received at multiple antennas of a receiver. At the receiver, eachdata stream is separated and extracted from the combined signal. Thisprocess is generally performed using a minimum mean squared error (MMSE)or MMSE-successive interference cancellation (SIC) algorithm.

In 3^(rd) Generation Partnership Project (3GPP) Long Term Evolution(LTE) systems, the base station transmits a Downlink (DL) grant to asubscriber station in a Physical Downlink Control Channel (PDCCH). Someframes later, the subscriber station transmits an Acknowledgement (ACK)or Negative Acknowledgement (NACK) to the base station.

SUMMARY OF THE INVENTION

A wireless communications network including a plurality of cellincluding at least one base station is provided. The base stationincludes a transmitter configured to transmit to the user equipment botha cell specific radio resource control (RRC) configuration comprising acell specific resource offset parameter for a physical uplink controlchannel (PUCCH) carrying an hybrid automatic repeat request(HARQ)-acknowledgement (ACK), and a user equipment (UE) specific RRCconfiguration comprising a UE specific RS base sequence parameter and anUE specific resource offset parameter for the PUCCH HARQ-ACK. The basestation further includes a receiver configured to receive the PUCCHcarrying the HARQ-ACK information which is generated based on either thecell specific RRC configuration or the UE specific RRC configuration.

A user equipment capable of receiving communications from a cellincluding at least one base station is provided. The user equipmentincludes a receiver configured to receive from the base station both acell specific radio resource control (RRC) configuration comprising acell specific resource offset parameter for a PUCCH carrying anHARQ-ACK, and a UE specific RRC configuration comprising a UE specificRS base sequence parameter and an UE specific resource offset parameterfor the PUCCH carrying the HARQ-ACK. The user equipment further includesa transmitter configured to transmit the PUCCH carrying the HARQ-ACKinformation which is generated based on either the cell specific RRCconfiguration or the UE specific RRC configuration.

A method for interference mitigation is provided. The method includestransmitting to a user equipment both a cell specific radio resourcecontrol (RRC) configuration comprising a cell specific resource offsetparameter for a PUCCH carrying an HARQ-ACK, and a specific RRCconfiguration comprising a UE specific RS base sequence parameter and anUE specific resource offset parameter for the PUCCH carrying theHARQ-ACK. The method further includes receiving the PUCCH which isgenerated based on either the cell specific RRC configuration or the UEspecific RRC configuration.

Before undertaking the DETAILED DESCRIPTION OF THE INVENTION below, itmay be advantageous to set forth definitions of certain words andphrases used throughout this patent document: the terms “include” and“comprise,” as well as derivatives thereof, mean inclusion withoutlimitation; the term “or,” is inclusive, meaning and/or; the phrases“associated with” and “associated therewith,” as well as derivativesthereof, may mean to include, be included within, interconnect with,contain, be contained within, connect to or with, couple to or with, becommunicable with, cooperate with, interleave, juxtapose, be proximateto, be bound to or with, have, have a property of, or the like; and theterm “controller” means any device, system or part thereof that controlsat least one operation, such a device may be implemented in hardware,firmware or software, or some combination of at least two of the same.It should be noted that the functionality associated with any particularcontroller may be centralized or distributed, whether locally orremotely. Definitions for certain words and phrases are providedthroughout this patent document, those of ordinary skill in the artshould understand that in many, if not most instances, such definitionsapply to prior, as well as future uses of such defined words andphrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIG. 1 illustrates an Orthogonal Frequency Division Multiple Access(OFDMA) wireless network that is capable of decoding data streamsaccording to embodiments of the present disclosure;

FIG. 2A is a high-level diagram of an OFDMA transmitter according toembodiments of the present disclosure;

FIG. 2B is a high-level diagram of an OFDMA receiver according toembodiments of the present disclosure;

FIG. 3 illustrates an exemplary OFDM frame in the LTE system accordingto embodiments of the present disclosure;

FIG. 4 illustrates a flow diagram for messages between a base stationand a subscriber station according to embodiments of the presentdisclosure;

FIG. 5 illustrates Channel Control Element (CCE) resources in a DLcarrier according to embodiments of the present disclosure;

FIG. 6 illustrates an LTE Physical Uplink Control Channel (PUCCH)resource partition in on RB in the Uplink (UL) carrier according toembodiments of the present disclosure;

FIG. 7 illustrates wireless network that is capable of decoding datastreams according to embodiments of the present disclosure;

FIGS. 8A and 8B illustrate PUCCH physical resource blocks that aredesignated to interfering subscribers according to embodiments of thepresent disclosure; and

FIG. 9 illustrates downlink resources where enhanced PDCCHs (E-PDCCHs)are placed in the physical downlink shared channel (PDSCH) regionsaccording to embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 through 9, discussed below, and the various embodiments used todescribe the principles of the present disclosure in this patentdocument are by way of illustration only and should not be construed inany way to limit the scope of the disclosure. Those skilled in the artwill understand that the principles of the present disclosure may beimplemented in any suitably arranged wireless communications network.

With regard to the following description, it is noted that the 3GPP LongTerm Evolution (LTE) term “node B” is another term for “base station”used below. Also, the LTE term “user equipment” or “UE” is another termfor “subscriber station” used below.

The following standards descriptions are hereby incorporated into thepresent disclosure as if fully set forth herein: 3GPP TechnicalSpecification No. 36.211, version 10.1.0, “E-UTRA, Physical Channels AndModulation”; 3GPP Technical Specification No. 36.212, version 10.1.0,“E-UTRA, Multiplexing And Channel Coding”; and 3GPP TechnicalSpecification No. 36.213, version 10.1.0, “E-UTRA, Physical LayerProcedures”.

FIG. 1 illustrates exemplary wireless network 100 that is capable ofdecoding data streams according to one embodiment of the presentdisclosure. In the illustrated embodiment, wireless network 100 includesbase station (BS) 101, base station (BS) 102, and base station (BS) 103.Base station 101 communicates with base station 102 and base station103. Base station 101 also communicates with Internet protocol (IP)network 130, such as the Internet, a proprietary IP network, or otherdata network.

Base station 102 provides wireless broadband access to network 130, viabase station 101, to a first plurality of user equipments withincoverage area 120 of base station 102. The first plurality of userequipments includes user equipment (UE) 111, user equipment (UE) 112,user equipment (UE) 113, user equipment (UE) 114, user equipment (UE)115 and user equipment (UE) 116. User equipment (UE) may be any wirelesscommunication device, such as, but not limited to, a mobile phone,mobile PDA and any mobile station (MS). In an exemplary embodiment, UE111 may be located in a small business (SB), UE 112 may be located in anenterprise (E), UE 113 may be located in a Wi-Fi hotspot (HS), UE 114may be located in a first residence, UE 115 may be located in a secondresidence, and UE 116 may be a mobile (M) device.

Base station 103 provides wireless broadband access to network 130, viabase station 101, to a second plurality of user equipments withincoverage area 125 of base station 103. The second plurality of userequipments includes user equipment 115 and user equipment 116. Inalternate embodiments, base stations 102 and 103 may be connecteddirectly to the Internet by means of a wired broadband connection, suchas an optical fiber, DSL, cable or T1/E1 line, rather than indirectlythrough base station 101.

In other embodiments, base station 101 may be in communication witheither fewer or more base stations. Furthermore, while only six userequipments are shown in FIG. 1, it is understood that wireless network100 may provide wireless broadband access to more than six userequipments. It is noted that user equipment 115 and user equipment 116are on the edge of both coverage area 120 and coverage area 125. Userequipment 115 and user equipment 116 each communicate with both basestation 102 and base station 103 and may be said to be operating inhandoff mode, as known to those of skill in the art.

In an exemplary embodiment, base stations 101-103 may communicate witheach other and with user equipments 111-116 using an IEEE-802.16wireless metropolitan area network standard, such as, for example, anIEEE-802.16e standard. In another embodiment, however, a differentwireless protocol may be employed, such as, for example, a HIPERMANwireless metropolitan area network standard. Base station 101 maycommunicate through direct line-of-sight or non-line-of-sight with basestation 102 and base station 103, depending on the technology used forthe wireless backhaul. Base station 102 and base station 103 may eachcommunicate through non-line-of-sight with user equipments 111-116 usingOFDM and/or OFDMA technique user equipments.

Base station 102 may provide a T1 level service to user equipment 112associated with the enterprise and a fractional T1 level service to userequipment 111 associated with the small business. Base station 102 mayprovide wireless backhaul for user equipment 113 associated with theWi-Fi hotspot, which may be located in an airport, café, hotel, orcollege campus. Base station 102 may provide digital subscriber line(DSL) level service to user equipments 114, 115 and 116.

User equipments 111-116 may use the broadband access to network 130 toaccess voice, data, video, video teleconferencing, and/or otherbroadband services. In an exemplary embodiment, one or more of userequipments 111-116 may be associated with an access point (AP) of aWi-Fi WLAN. User equipment 116 may be any of a number of mobile devices,including a wireless-enabled laptop computer, personal data assistant,notebook, handheld device, or other wireless-enabled device. Userequipments 114 and 115 may be, for example, a wireless-enabled personalcomputer, a laptop computer, a gateway, or another device.

Dotted lines show the approximate extents of coverage areas 120 and 125,which are shown as approximately circular for the purposes ofillustration and explanation only. It should be clearly understood thatthe coverage areas associated with base stations, for example, coverageareas 120 and 125, may have other shapes, including irregular shapes,depending upon the configuration of the base stations and variations inthe radio environment associated with natural and man-made obstructions.

Also, the coverage areas associated with base stations are not constantover time and may be dynamic (expanding or contracting or changingshape) based on changing transmission power levels of the base stationand/or the user equipments, weather conditions, and other factors. In anembodiment, the radius of the coverage areas of the base stations, forexample, coverage areas 120 and 125 of base stations 102 and 103, mayextend in the range from less than 2 kilometers to about fiftykilometers from the base stations.

As is well known in the art, a base station, such as base station 101,102, or 103, may employ directional antennas to support a plurality ofsectors within the coverage area. In FIG. 1, base stations 102 and 103are depicted approximately in the center of coverage areas 120 and 125,respectively. In other embodiments, the use of directional antennas maylocate the base station near the edge of the coverage area, for example,at the point of a cone-shaped or pear-shaped coverage area.

The connection to network 130 from base station 101 may comprise abroadband connection, for example, a fiber optic line, to serverslocated in a central office or another operating companypoint-of-presence. The servers may provide communication to an Internetgateway for internet protocol-based communications and to a publicswitched telephone network gateway for voice-based communications. Inthe case of voice-based communications in the form of voice-over-IP(VoIP), the traffic may be forwarded directly to the Internet gatewayinstead of the PSTN gateway. The servers, Internet gateway, and publicswitched telephone network gateway are not shown in FIG. 1. In anotherembodiment, the connection to network 130 may be provided by differentnetwork nodes and equipment.

In accordance with an embodiment of the present disclosure, one or moreof base stations 101-103 and/or one or more of user equipments 111-116comprises a receiver that is operable to decode a plurality of datastreams received as a combined data stream from a plurality of transmitantennas using an MMSE-SIC algorithm. As described in more detail below,the receiver is operable to determine a decoding order for the datastreams based on a decoding prediction metric for each data stream thatis calculated based on a strength-related characteristic of the datastream. Thus, in general, the receiver is able to decode the strongestdata stream first, followed by the next strongest data stream, and soon. As a result, the decoding performance of the receiver is improved ascompared to a receiver that decodes streams in a random orpre-determined order without being as complex as a receiver thatsearches all possible decoding orders to find the optimum order.

FIG. 2A is a high-level diagram of an orthogonal frequency divisionmultiple access (OFDMA) transmit path. FIG. 2B is a high-level diagramof an orthogonal frequency division multiple access (OFDMA) receivepath. In FIGS. 2A and 2B, the OFDMA transmit path is implemented in basestation (BS) 102 and the OFDMA receive path is implemented in userequipment (UE) 116 for the purposes of illustration and explanationonly. However, it will be understood by those skilled in the art thatthe OFDMA receive path may also be implemented in BS 102 and the OFDMAtransmit path may be implemented in UE 116.

The transmit path in BS 102 comprises channel coding and modulationblock 205, serial-to-parallel (S-to-P) block 210, Size N Inverse FastFourier Transform (IFFT) block 215, parallel-to-serial (P-to-S) block220, add cyclic prefix block 225, up-converter (UC) 230. The receivepath in UE 116 comprises down-converter (DC) 255, remove cyclic prefixblock 260, serial-to-parallel (S-to-P) block 265, Size N Fast FourierTransform (FFT) block 270, parallel-to-serial (P-to-S) block 275,channel decoding and demodulation block 280.

At least some of the components in FIGS. 2A and 2B may be implemented insoftware while other components may be implemented by configurablehardware or a mixture of software and configurable hardware. Inparticular, it is noted that the FFT blocks and the IFFT blocksdescribed in this disclosure document may be implemented as configurablesoftware algorithms, where the value of Size N may be modified accordingto the implementation.

Furthermore, although this disclosure is directed to an embodiment thatimplements the Fast Fourier Transform and the Inverse Fast FourierTransform, this is by way of illustration only and should not beconstrued to limit the scope of the disclosure. It will be appreciatedthat in an alternate embodiment of the disclosure, the Fast FourierTransform functions and the Inverse Fast Fourier Transform functions mayeasily be replaced by Discrete Fourier Transform (DFT) functions andInverse Discrete Fourier Transform (IDFT) functions, respectively. Itwill be appreciated that for DFT and IDFT functions, the value of the Nvariable may be any integer number (i.e., 1, 2, 3, 4, etc.), while forFFT and IFFT functions, the value of the N variable may be any integernumber that is a power of two (i.e., 1, 2, 4, 8, 16, etc.).

In BS 102, channel coding and modulation block 205 receives a set ofinformation bits, applies coding (e.g., Turbo coding) and modulates(e.g., QPSK, QAM) the input bits to produce a sequence offrequency-domain modulation symbols. Serial-to-parallel block 210converts (i.e., de-multiplexes) the serial modulated symbols to paralleldata to produce N parallel symbol streams where N is the IFFT/FFT sizeused in BS 102 and UE 116. Size N IFFT block 215 then performs an IFFToperation on the N parallel symbol streams to produce time-domain outputsignals. Parallel-to-serial block 220 converts (i.e., multiplexes) theparallel time-domain output symbols from Size N IFFT block 215 toproduce a serial time-domain signal. Add cyclic prefix block 225 theninserts a cyclic prefix to the time-domain signal. Finally, up-converter230 modulates (i.e., up-converts) the output of add cyclic prefix block225 to RF frequency for transmission via a wireless channel. The signalmay also be filtered at baseband before conversion to RF frequency.

The transmitted RF signal arrives at UE 116 after passing through thewireless channel and reverse operations to those at BS 102 areperformed. Down-converter 255 down-converts the received signal tobaseband frequency and remove cyclic prefix block 260 removes the cyclicprefix to produce the serial time-domain baseband signal.Serial-to-parallel block 265 converts the time-domain baseband signal toparallel time domain signals. Size N FFT block 270 then performs an FFTalgorithm to produce N parallel frequency-domain signals.Parallel-to-serial block 275 converts the parallel frequency-domainsignals to a sequence of modulated data symbols. Channel decoding anddemodulation block 280 demodulates and then decodes the modulatedsymbols to recover the original input data stream.

Each of base stations 101-103 may implement a transmit path that isanalogous to transmitting in the downlink to user equipments 111-116 andmay implement a receive path that is analogous to receiving in theuplink from user equipments 111-116. Similarly, each one of userequipments 111-116 may implement a transmit path corresponding to thearchitecture for transmitting in the uplink to base stations 101-103 andmay implement a receive path corresponding to the architecture forreceiving in the downlink from base stations 101-103.

The present disclosure describes methods and systems to conveyinformation relating to base station configuration to user equipmentsand, more specifically, to relaying base station antenna configurationto user equipments. This information can be conveyed through a pluralityof methods, including placing antenna configuration into aquadrature-phase shift keying (QPSK) constellation (e.g., n-quadratureamplitude modulation (QAM) signal, wherein n is 2^x) and placing antennaconfiguration into the error correction data (e.g., cyclic redundancycheck (CRC) data). By encoding antenna information into either the QPSKconstellation or the error correction data, the base stations 101-103can convey base stations 101-103 antenna configuration without having toseparately transmit antenna configuration. These systems and methodsallow for the reduction of overhead while ensuring reliablecommunication between base stations 101-103 and a plurality of userequipments.

In some embodiments disclosed herein, data is transmitted using QAM. QAMis a modulation scheme that conveys data by modulating the amplitude oftwo carrier waves. These two waves are referred to as quadraturecarriers, and are generally out of phase with each other by 90 degrees.QAM may be represented by a constellation that comprises 2^x points,where x is an integer greater than 1. In the embodiments discussedherein, the constellations discussed will be four point constellations(4-QAM). In a 4-QAM constellation a 2 dimensional graph is representedwith one point in each quadrant of the 2 dimensional graph. However, itis explicitly understood that the innovations discussed herein may beused with any modulation scheme with any number of points in theconstellation. It is further understood that with constellations withmore than four points, additional information (e.g., reference powersignal) relating to the configuration of the base stations 101-103 maybe conveyed consistent with the disclosed systems and methods.

It is understood that the transmitter within base stations 101-103performs a plurality of functions prior to actually transmitting data.In the 4-QAM embodiment, QAM modulated symbols are serial-to-parallelconverted and input to an inverse fast Fourier transform (IFFT). At theoutput of the IFFT, N time-domain samples are obtained. In the disclosedembodiments, N refers to the IFFT/fast Fourier transform (FFT) size usedby the OFDM system. The signal after IFFT is parallel-to-serialconverted and a cyclic prefix (CP) is added to the signal sequence. Theresulting sequence of samples is referred to as an OFDM symbol.

At the receiver within the user equipment, this process is reversed, andthe cyclic prefix is first removed. Then the signal isserial-to-parallel converted before being fed into the FFT. The outputof the FFT is parallel-to-serial converted, and the resulting QAMmodulation symbols are input to the QAM demodulator.

The total bandwidth in an OFDM system is divided into narrowbandfrequency units called subcarriers. The number of subcarriers is equalto the FFT/IFFT size N used in the system. In general, the number ofsubcarriers used for data is less than N because some subcarriers at theedge of the frequency spectrum are reserved as guard subcarriers. Ingeneral, no information is transmitted on guard subcarriers.

FIG. 3 illustrates an exemplary OFDM frame in the LTE system accordingto embodiments of the present disclosure. The embodiment of the frame300 shown in FIG. 3 is for illustration only. Other embodiments of theLTE frames could be used without departing from the scope of thisdisclosure.

Time resources in the LTE system are partitioned into ten millisecond(10 msec) frames 300. Each frame 300 is further partitioned into ten(10) sub-frames 310-319. Each sub-frame 310-319 further is divided intotwo time slots 320, 325. The two time slots 320, 325 are half amillisecond (0.5 msec) each.

FIG. 4 illustrates a flow diagram for messages between a base stationand a user equipment according to embodiments of the present disclosure.The embodiment of the flow diagram shown in FIG. 4 is for illustrationonly. Other embodiments of the flow diagram could be used withoutdeparting from the scope of this disclosure.

BS 102 schedules and initiates a DL transmission to UE 116. For eachsub-frame 310-319 in the DL transmission, BS 102 sends DL ControlInformation (DCI) to UE 116 in the PDCCH. The DCI is located within thefirst few OFDM symbols in the sub-frame 310-319. For example, the DCIcan be located in one or more of sub-frames 310, 311 and 312. The DCIcan be located in one of the symbols, used as the DL carrier 330, in thetime slot 320, 325 (as illustrated in FIG. 3). The DCI indicates theallocated RBs for UE 116 as well as additional information.

Upon reception of the DL grant targeted to UE 116, UE 116 attempts todecode the transmitted message regarding the allocated RBs. Dependingupon the decoding results for each transmitted sub-frame 310-319, UE 116sends hybrid-ARQ bits (or uplink ACK/NACK bits) to BS 102 a fewsub-frames later. For example, in a Frequency-Division Duplex (FDD)system, UE 116 transmits the ACK/NACK response 405 in sub-frame n inresponse to the decoding result for the DCI 410 received in sub-framen−4.

FIG. 5 illustrates Channel Control Element (CCE) resources in a DLcarrier. The embodiment of the CCEs 500 shown in FIG. 5 is forillustration only. Other embodiments of the CCEs could be used withoutdeparting from the scope of this disclosure.

A PDCCH that carries DCI is transmitted on an aggregation of one orseveral consecutive CCEs 500. The CCEs 500 available in the DL carrier330 are numbered from 0 to N_(CCE)−1.

The CCEs 500 are control elements used for sending downlink grant. UE116 reads the CCEs 500 to determine the downlink grant allocated to UE116. For example, if CCE ‘012’ is sent to UE 116, UE 116 determines thatCCE ‘012’ are allocated to UE 116. Therefore, UE 116 not only looks atthe content of the CCE but also the location where the content is sent.Therefore, in some embodiments, UE 116 knows which resources to use torespond (e.g., ACK/NACK) based on what CCEs are used for the downlinkgrant.

FIG. 6 illustrates an LTE Physical Uplink Control Channel (PUCCH)resource partition in on RB in the Uplink (UL) carrier. The embodimentof the PUCCH partition 600 shown in FIG. 6 is for illustration only.Other embodiments of the CCEs could be used without departing from thescope of this disclosure.

UL ACK/NACK (AN) bits are transmitted on PUCCH formats 1a and 1b.Resources used for transmission of PUCCH format 1a/1b are represented bythe non-negative index n_(PUCCH) ⁽¹⁾. PUCCH resource index n_(PUCCH) ⁽¹⁾for hybrid automatic repeat request (HARQ)-ACK/NCAK determines anorthogonal cover 605 and a cyclic shift 610. The orthogonal cover 605and cyclic shift 610 indicate a unique resource. For example, thirty six(e.g., 3×12) PUCCH AN resources are available in one RB.

FIG. 7 illustrates network 700 that is capable of decoding data streamsaccording to embodiments of the present disclosure. The embodiment ofthe network 700 shown in FIG. 7 is for illustration only. Otherembodiments could be used without departing from the scope of thisdisclosure.

In the illustrated embodiment, user equipments (UEs) 713 and 714 areconnected to the base stations (BS) 701 having the cell ID of N_(ID,1)^(cell), through to local base station 701 a and 701 b. User equipment711 is directly connected to BS 701. Alternatively, UEs 712 and 715 areconnected to BS 702 having the cell ID of N_(ID,2) ^(cell).

UEs 713 and 714 connected to BS 701 are located far from each other. UEs712 and 715 connected to different BS 702 are also far from each other.However, UEs 711 and 712 are closely located but connected to twodifferent base stations, that is, UE 711 is connected to BS 701 and SS712 is connected to BS 702.

The user equipment that are closely located to interfere with anotheruser equipment above a specified threshold, and connected to differentcell from another user equipment respectively is denoted as ‘highinterfering user equipment’ for this disclosure. For example, UEs 711and 712 illustrated in FIG. 7 are the high interfering user equipments.The specified threshold can be adjusted in various levels to meet theservice provider's requirements.

In certain embodiments, the network 700 can transmit to the userequipments both a cell specific radio resource control (RRC)configuration and an UE specific RRC configuration. The cell specificRRC configuration can include a cell specific resource offset parameterfor the PUCCH HARQ-ACK. The UE specific configuration can include a UEspecific RS base sequence parameter and a UE specific resource offsetparameter for the PUCCH HARQ-ACK.

When the UE specific RRC configuration is applicable to the userequipment, the user equipment can transmit an UE specific PUCCH carryingHARQ-ACK, which is generated with an UE specific RS generated using UEspecific RS base sequence parameter and an UE specific resource offsetparameter for the PUCCH HARQ-ACK.

When the UE specific RRC configuration is not applicable to the userequipment, the user equipment can transmit a cell specific PUCCHcarrying an HARQ-ACK, which is generated with the cell specificreference signal generated using the cell specific resource offsetparameter for a PUCCH HARQ-ACK.

In certain embodiments, the network 700 can transmit the identical UEspecific RS base sequence and UE specific resource offset parameters tothe UEs 711 and 712 whose interference are higher than the specifiedthreshold. Thus, the high interfering UEs 711 and 712 can transmit thecoordinated PUCCH carrying HARQ-ACK information, which is generatedusing the identical UE specific RRC configuration.

In certain embodiments, the network 700 can transmit UE specific RRCconfiguration to the UEs such as UE 713, 714 and 715 whose interferencesare lower than the specified threshold. Thus, the low interfering UEscan transmit the UE specific PUCCHs carrying HARQ-ACK information, whichare generated based the UE specific RRC configurations.

In the embodiment, the network 700 can transmit the identical UEspecific RS configuration base sequence parameter to the UEs 711 and712. UEs 711 and 712 transmit the PUCCH carrying HARQ-ACK, using thesame RS base sequence 1. Thus, UEs 711 and 712 cause a small ULinterference to each other. On the other hand UEs 713, 714 and 715transmit the UE specific PUCCH generated with the UE specific RS basesequences, which are RS base sequence 2, 3, and 4 respectively. Thus,the PUCCHs transmitted from the user equipments can be orthogonal eachother. As mentioned above, the threshold to determine high interferenceor low interference can be adjusted to meet the service provider'svarious requirements.

FIGS. 8A and 8B illustrate PUCCH physical resource blocks that aredesignated to the interfering user equipments according to embodimentsof the present disclosure. The embodiments of the PUCCH physicalresource blocks shown in FIGS. 8A and 8B are for illustration only.Other embodiments could be used without departing from the scope of thisdisclosure. UEs 711 and 712 transmit the coordinated PUCCH carryingHARQ-ACK, using the same RS base sequence 1. Thus, UEs 711 and 712 canreduce UL interference each other.

In certain embodiments, a resource index number for the PUCCH, n_(PUCCH)⁽¹⁾, is determined by the following equation:n _(PUCCH) ⁽¹⁾ =n _(CCE) +N _(PUCCH) ⁽¹⁾  [EQN 1]

In Equation 1, n_(CCE) is a number of the smallest channel controlelement (CCE) used for transmission of a corresponding downlink controlinformation scheduling a PDSCH for which the PUCCH carries the HARQ-ACKinformation, and N_(PUCCH) ⁽¹⁾ is the UE specific resource offsetparameter in case the UE specific RRC configuration is applicable to theuser equipment; otherwise N_(PUCCH) ⁽¹⁾ is the cell specific resourceoffset parameter.

In certain embodiments, the UE specific RRC configuration can contain anindication parameter indicating whether the UE specific RRCconfiguration or the cell specific RRC configuration is applicable tothe user equipment. The indication parameter can have a value of TRUE orFALSE, wherein TRUE means that the UE specific RRC configuration isapplicable to the user equipment and FALSE means that the cell specificRRC configuration is applicable to the user equipment.

In certain embodiments, N_(PUCCH) ⁽¹⁾ can be derived from at least oneof the CSI-RS configuration numbers associated with non-zero CSI-RStransmission power defined in Table 6.10.5.2-1 in 3GPP TS 36.211,version 10.1.0, “E-UTRA, Physical Channels And Modulation”, the contentsof which are hereby incorporated by reference and which is denoted asNCSI-RS for this disclosure as follows:

NCSI-RS can be the CSI-RS configuration number of the primary basestation from which user equipment receives PDCCH;

NCSI-RS can be the smallest CSI-RS configuration number out of all suchCSI-RS configuration numbers; NCSI-RS can be the largest CSI-RSconfiguration number out of all such CSI-RS configuration numbers; orNCSI-RS can be the CSI-RS configuration number with the smallestsubframe configuration, an RRC parameter to configure CSI-RS subframeperiodicity. Ties with more than one configuration numbers with thesmallest subframe configuration, can be broken with either the smallestor the largest CSI-RS configuration number.

In certain embodiments, the network can semi-statically configure a setof N candidates for N_(PUCCH) ⁽¹⁾ by RRC configuration, the networkdynamically indicates one N_(PUCCH) ⁽¹⁾ out of the N candidates bydynamic signaling.

For example, the number of the N candidates can be four and a two-bitinformation element (IE) is included in the PDCCH, e.g., correspondingto the downlink grant to generate four (4) candidate n_(PUCCH) ⁽¹⁾s.n_(PUCCH) ⁽¹⁾ can be selected among four (4) candidate n_(PUCCH) ⁽¹⁾s,depending on the value of IE as followed in exemplary TABLE 1.

TABLE 1 The two-bit IE indicating n_(PUCCH) ⁽¹⁾ Indicated n_(PUCCH) ⁽¹⁾value 00 The first n_(PUCCH) ⁽¹⁾ value configured by RRC 01 The secondn_(PUCCH) ⁽¹⁾ value configured by RRC 10 The third n_(PUCCH) ⁽¹⁾ valueconfigured by RRC 11 The fourth n_(PUCCH) ⁽¹⁾ value configured by RRC

In certain embodiments, the number of the candidates N can be two and aone-bit information element (IE) is included in the PDCCH, e.g.,corresponding to the downlink grant to generate two (2) candidaten_(PUCCH) ⁽¹⁾s. One n_(PUCCH) ⁽¹⁾ can be selected from two (2) candidaten_(PUCCH) ⁽¹⁾s, depending on the value of IE as followed in exemplaryTABLE 2.

TABLE 2 The 1-bit IE indicating n_(PUCCH) ⁽¹⁾ Indicated n_(PUCCH) ⁽¹⁾value 0 The first n_(PUCCH) ⁽¹⁾ value configured by RRC 1 The secondn_(PUCCH) ⁽¹⁾ value configured by RRC

In certain embodiments, a resource index number for the PUCCH, n_(PUCCH)⁽¹⁾, is determined by the following equation:n _(PUCCH) ⁽¹⁾ =n _(CCE) +N _(PUCCH) ⁽¹⁾ +N _(PUCCH,offset) ⁽¹⁾  [EQN 2]

In Equation 2, n_(CCE) is the number of the smallest channel controlelement (CCE) used for transmission of a corresponding downlink controlinformation scheduling a PDSCH for which the PUCCH carries the HARQ-ACKinformation and N_(PUCCH,offset) ⁽¹⁾ is the UE specific resource offsetparameter in case the UE specific RRC configuration is applicable to theuser equipment; otherwise N_(PUCCH,offset) ⁽¹⁾ is the cell specificresource offset parameter.

In certain embodiments, N_(PUCCH,offset) ⁽¹⁾ is derived from at leastone of NCSI-RS as follows:

NCSI-RS can be the CSI-RS configuration number of the primary basestation from which the user equipment receives PDCCH; NCSI-RS can be thesmallest CSI-RS configuration number out of all such CSI-RSconfiguration numbers; NCSI-RS can be the largest CSI-RS configurationnumber out of all such CSI-RS configuration numbers; or NCSI-RS can bethe CSI-RS configuration number with the smallest subframeConfig-r10, anRRC parameter to configure CSI-RS subframe periodicity. Ties with morethan one configuration numbers with the smallest subframe configuration,can be broken with either the smallest or the largest CSI-RSconfiguration number.

FIG. 9 illustrates downlink resource where enhanced PDCCHs (E-PDCCHs)are placed in the PDSCH regions. The embodiment of the downlinkresources shown in FIG. 9 is for illustration only. Other embodimentscould be used without departing from the scope of this disclosure.

E-PDCCH 905 increases downlink (DL) control capacity within a basestation and mitigates inter-cell interference for downlink control. Incertain embodiments, a PUCCH format 1/1a/1b resource can be generatedwith reference signal (RS) base sequence that is depending on thelocation of DL grant, that is, whether PDCCH or E-PDCCH 905 is used forconveying a DL grant associated with the HARQ-ACK feedback.

In certain embodiments, a user equipment generates userequipment-specific RS base sequence for a PUCCH format 1/1a/1b when theuser equipment receives the corresponding downlink control informationcarried in the E-PDCCH 905 region as shown in exemplary TABLE 3. Forn_(PUCCH) ⁽¹⁾ mapping when the user equipment receives the DL grant inthe E-PDCCH 905 region, Equation 1 or 2 can be used with n_(CCE) beingthe first CCE number carrying the DL grant in the E-PDCCH 905 region.

TABLE 3 Base sequence DL grant location generation method n_(PUCCH) ⁽¹⁾mapping PDCCH Cell-specific n_(CCE) derived within the PDCCH regionE-PDCCH User Equipment- n_(CCE) derived within specific the E-PDCCHregion

According to one embodiment of the present disclosure, an user equipmentcan generate a uplink (UL) reference signal (RS) base sequence r_(u,v)(n), where v is equal to 0 for PUCCH and v is configured to be 0or 1 for SRS by RRC, and a sequence group number u is derived from thefollowing equation:u=(f _(gh)(n _(s))+f _(ss))mod 30,  [EQN 3]

In Equation 3, f_(gh)(n_(s)) is the group hopping pattern and f_(ss) issequence-shift pattern. f_(ss) is equal to f_(ss) ^(PUCCH), thesequence-shift pattern for PUCCH when f_(ss) is used for generatingphysical uplink control channel (PUCCH), or f_(ss) is equal to f_(ss)^(PUSCH), the sequence-shift pattern for PUSCH when f_(ss) is used forgenerating physical uplink shared channel (PUSCH).

The group-hopping pattern f_(gh)(n_(s)) is the same for both PUSCH andPUCCH and given by:

$\begin{matrix}{{f_{gh}\left( n_{s} \right)} = \left\{ \begin{matrix}0 & {{if}\mspace{14mu}{group}\mspace{14mu}{hopping}\mspace{14mu}{is}\mspace{14mu}{disabled}} \\{\left( {\sum\limits_{i = 0}^{7}{{c\left( {{8\; n_{s}} + i} \right)} \cdot 2^{i}}} \right){mod}\; 30} & {{{if}\mspace{14mu}{group}\mspace{14mu}{hopping}\mspace{14mu}{is}\mspace{14mu}{enabled}},}\end{matrix} \right.} & \left\lbrack {{EQN}\mspace{14mu} 4} \right\rbrack\end{matrix}$

In Equation 4, the pseudo-random sequence c(i) is defined by section 7.2in 3GPP TS No. 36.211, version 10.1.0, “E-UTRA, Physical Channels AndModulation”, the contents of which are hereby incorporated by referencein their entirety. The pseudo-random sequence generator shall beinitialized with c_(init,SGH) at the beginning of each radio frame.Sequence hopping only applies for reference-signals of length M_(sc)^(RS)≧6N_(sc) ^(RB). For reference-signals of length M_(sc)^(RS)<6N_(sc) ^(RB), the base sequence number v within the base sequencegroup is given by v=0. For reference-signals of length M_(sc)^(RS)≧6N_(sc) ^(RB), the base sequence number v within the base sequencegroup in slot n_(s) is defined by:

$\begin{matrix}{v = \left\{ \begin{matrix}{c\left( n_{s} \right)} & \begin{matrix}{{if}\mspace{14mu}{group}\mspace{14mu}{hopping}\mspace{14mu}{is}\mspace{14mu}{disabled}\mspace{14mu}{and}\mspace{14mu}{sequence}\mspace{14mu}{hopping}} \\{\mspace{14mu}{{is}\mspace{14mu}{enabled}}}\end{matrix} \\0 & {otherwise}\end{matrix} \right.} & \left\lbrack {{EQN}\mspace{14mu} 5} \right\rbrack\end{matrix}$

The parameter sequence-hopping-enabled provided by RRC determineswhether sequence hopping is enabled or not. Sequence hopping for PUSCHcan be disabled for a certain user equipment through the higher-layerparameter Disable-sequence-group-hopping despite being enabled on a cellbasis. The pseudo-random sequence generator PUSCH shall be initializedwith c_(init)=c_(init,SGH)·2⁵+f_(ss) ^(PUSCH) at the beginning of eachradio frame.

In embodiments where sequence group hopping (SGH) is turned on, thesequence hopping (SH) initialization seed is determined by:c _(init) =c _(init,SGH) +f _(ss) ^(PUSCH),  [EQN 6]

In Equation 6, where f_(ss) ^(PUSCH) is sequence-shift pattern for PUSCHand c_(init,SGH) is the random seed for sequence group hopping (SGH).

In certain embodiments, the random seed for sequence group hopping (SGH)c_(init) can be configured such that the interfering user equipments areassigned to same uplink (UL) reference signal (RS) base sequence.

In embodiments where sequence group hopping (SGH) is turned off,f_(gh)(n_(s)) is equal to 0 and the sequence group number u isdetermined by only f_(ss), or u=f_(ss) mod 30. According to anotherembodiment of the present disclosure, the sequence-shift pattern f_(ss)is configured using the following equation:

For physical uplink control channel (PUCCH) and sounding referencesignal (SRS),f _(ss) ^(PUCCH)=(N)mod 30  [EQN 7]

In Equation 7, N is the UE specific RS base sequence parameter in casethe UE specific RRC configuration is applicable to the user equipment;otherwise N is the cell identification of the cell. N can be replacedwith the sum of N_(ID) ^(cell) and N_(UEoffset) ^(PUCCH) which isconfigured by RRC configuration.

For physical uplink shared channel (PUSCH) demodulation reference signal(DM RS),f _(ss) ^(PUSCH)=(f _(ss) ^(PUCCH)+Δ′_(ss))mod 30,  [EQN 8]

In Equation 8, f_(ss) ^(PUCCH) is sequence-shift pattern for PUCCH andΔ′_(ss) is configured by RRC configuration.

In certain embodiments, Δ′_(ss) can be set to be Δ_(ss) as defined in3GPP TS 36.211 version 8.9.0. which is hereby incorporated into thepresent disclosure as if fully set forth herein, and N_(UEoffset)^(PUCCH) can be configured by RRC such as RRC or by dynamic signalingsuch that the interfering user equipments are assigned to same uplink(UL) reference signal (RS) base sequence.

In another embodiment of the present disclosure, N_(UEoffset) ^(PUCCH)can be zero and Δ′_(ss) can be user equipment-specifically configured byRRC such as RRC or dynamic signaling such that the high interfering userequipments are assigned to same uplink (UL) reference signal (RS) basesequence. Consequently, the sequence-shift patterns of PUCCH, PUSCH DMRS and SRS can be user equipment-specifically configured for the userequipments.

In certain embodiments, both Δ′_(ss) and N_(UEoffset) ^(PUCCH) can beconfigured by UE specific RRC configuration or dynamic signaling suchthat the high interfering user equipments are assigned to the sameuplink (UL) reference signal (RS) base sequence parameter.

In certain embodiments, N_(UEoffset) ^(PUCCH) value can be configuredfrom {0, 1, . . . , 29} by RRC or dynamic signaling such that theinterfering user equipments are assigned to same uplink (UL) referencesignal (RS) base sequence.

In certain embodiments, Δ′_(ss) value can be configured from {0, 1, . .. , 29} by RRC or dynamic signaling such that the interfering userequipments are assigned to same uplink (UL) reference signal (RS) basesequence.

In certain embodiments, Δ′_(ss) can be dynamically signaled in an uplink(UL) grant, e.g., downlink control indication (DCI) format 0 or DCIformat 4. The dynamic signaling selects one Δ′_(ss) value out of Ncandidate Δ′_(ss) values such that the high interfering user equipmentsare assigned to same uplink (UL) reference signal (RS) base sequence.

In certain embodiments, Δ′_(ss) value is configured by RRC from {0, 1, .. . , 29} such that the high interfering user equipments are assigned tosame uplink (UL) reference signal (RS) base sequence.

In certain embodiments, the network can semi-statically configure a setof N candidates for Δ′O_(ss) by RRC configuration, the networkdynamically select one Δ′_(ss) out of the N candidates by PDCCHsignaling such that the high interfering user equipments are assigned tosame uplink (UL) reference signal (RS) base sequence.

For example, the number of the candidates N can be four and a two-bitinformation element (IE) can be included in the uplink (UL) grant as setin the following exemplary TABLE 4.

TABLE 4 The two-bit IE indicating Δ_(SS)′ Indicated Δ_(SS)′ value 00 Thefirst Δ_(SS)′ value configured by RRC 01 The second Δ_(SS)′ valueconfigured by RRC 10 The third Δ_(SS)′ value configured by RRC 11 Thefourth Δ_(SS)′ value configured by RRC

In another example, the number of the candidates N can be two, and aone-bit information element (IE) can be included in the UL grant as setin the following exemplary TABLE 5.

TABLE 5 The one-bit IE indicating Δ_(SS)′ Indicated Δ_(SS)′ value 0 Thefirst Δ_(SS)′ value configured by RRC 1 The second Δ_(SS)′ valueconfigured by RRC

In certain embodiments, for aperiodic SRS (A-SRS), N_(UEoffset) ^(PUCCH)is signaled in a transmission grant, which can be either downlink (DL)grant or uplink (UL) grant such that the high interfering userequipments are assigned to same uplink (UL) reference signal (RS) basesequence.

The N candidate N_(UEoffset) ^(PUCCH) values are configured by a highlayer such as RRC or dynamic signaling. For instance, N candidateN_(UEoffset) ^(PUCCH)s values has a group of {0, 1, . . . , 29}, or theN candidate N_(UEoffset) ^(PUCCH) can be indicated as Δ′_(ss) isindicated in TABLE 4 or TABLE 5.

In certain embodiments in which the SGH is turned off, for aligning theRS base sequence for the high interfering user equipments' PUCCHs, basestation 701 can configure N_(UEoffset) ^(PUCCH)=u−N_(ID,1) ^(cell) foruser equipment 711 and base station 702 can configure N_(UEoffset)^(PUCCH)=u−N_(ID,2) ^(cell) for user equipment 712.

In certain embodiments, sequence-shift pattern f_(ss) is configuredusing the following equation:

For physical uplink control channel (PUCCH) and sounding referencesignal (SRS),f _(ss) ^(PUCCH)=(N _(ID) ^(cell) +N _(UEoffset) ^(PUCCH))mod 30  [EQN9];and

physical uplink shared channel (PUSCH) demodulation reference signal (DMRS),f _(ss) ^(PUSCH)=(f _(ss) ^(PUCCH)+Δ_(ss) −N _(UEoffset) ^(PUCCH))mod30=(N _(ID) ^(cell)+Δ_(ss))mod 30  [EQN 10]

N_(UEoffset) ^(PUCCH) can be configured by RRC or by dynamic signalingsuch that the high interfering user equipments are assigned to sameuplink (UL) reference signal (RS) base sequence.

In certain embodiments, at least one of the sequence-shift patternsf_(ss) ^(PUCCH) and f_(ss) ^(PUSCH) can be configured by RRC or bydynamic signaling, where f_(ss) ^(PUSCH) or f_(ss) ^(PUSCH) can beconfigured from {0, 1, . . . , 29} such that the high interfering userequipments are assigned to same uplink (UL) reference signal (RS) basesequence.

In certain embodiments, the network can semi-statically configure a setof N candidates for f_(ss) ^(PUSCH) by RRC configuration and the networkdynamically select one f_(ss) ^(PUSCH) out of the N candidates by PDCCHsignaling such that the high interfering user equipments are assigned tosame UL RS base sequence. For example, the number of the candidates Ncan be four and a two-bit information element (IE) can be included inthe uplink (UL) grant as set in the following TABLE 8:

TABLE 8 The two-bit IE indicating f_(SS) ^(PUSCH) Indicated f_(SS)^(PUSCH) value 00 The first f_(SS) ^(PUSCH) value configured by RRC 01The second f_(SS) ^(PUSCH) value configured by RRC 10 The third f_(SS)^(PUSCH) value configured by RRC 11 The fourth f_(SS) ^(PUSCH) valueconfigured by RRC

In another example, the number of the candidates N can be two, and aone-bit information element (IE) is included in the UL grant as set inthe following TABLE 9.

TABLE 9 The one-bit IE indicating f_(SS) ^(PUSCH) Indicated f_(SS)^(PUSCH) value 0 The first f_(SS) ^(PUSCH) value configured by RRC 1 Thesecond f_(SS) ^(PUSCH) value configured by RRC

In another embodiment, for aperiodic SRS (A-SRS), f_(ss) ^(PUCCH) can besignaled in a transmission grant, which can be either downlink (DL)grant or uplink (UL) grant configured such that the high interferinguser equipments are assigned to same uplink (UL) reference signal (RS)base sequence. The N candidate f_(ss) ^(PUCCH) values can be configuredby a high layer such as RRC or dynamic signaling. For example, Ncandidate f_(ss) ^(PUCCH)s values has a group of {0, 1, . . . , 29}, orthe N candidate f_(ss) ^(PUCCH) can be indicated as f_(ss) ^(PUSCH)indicated in TABLE 8 or TABLE 9.

According to the present disclosure, the PUCCH decoding performance isimproved. That is, the decoding failure probability with the sametransmission power is decreased. The performance gain thanks to the UEspecific RS base sequence configuration mainly comes from the followingaspects: Reduced PUCCH interference as now the two PUCCH signals areorthogonally multiplexed and Cooperation gain in case of UL CooperativeMulti-Point (CoMP) reception in which case two cells cooperative todecode the PUCCHs generated with same RS base sequence. In coordinatemultipoint (CoMP) scenario 4 where a large number of user equipments areconnected to a same macro base station, uplink cell splitting gain canbe increased by assigning UE specific RRC configuration.

As used in this disclosure, coordinated multipoint (CoMP) transmissionpoints (TPs) refer to transmitters associated with a CoMP transmissionto a user equipment (UE) in a subframe. TPs can include remote radioheads (RRHs), macro eNodeBs, femto eNodeBs, pico eNodeBs, base stations,and the like. In some embodiments, CoMP TPs can have different cell IDs.In other embodiments, CoMP TPs can share the same cell IDs. Coordinatedmultipoint (COMP) reception points (RPs) refer to receivers associatedwith a CoMP transmission from a user equipment (UE) in a subframe. RPscan include remote radio heads (RRHs), macro eNodeBs, femto eNodeBs,pico eNodeBs, base stations, and the like. In some embodiments, CoMP RPscan have different cell IDs. In other embodiments, CoMP RPs can sharethe same cell IDs.

Although the present disclosure has been described with an exemplaryembodiment, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present disclosure encompasssuch changes and modifications as fall within the scope of the appendedclaims.

What is claimed is:
 1. A user equipment capable of receivingcommunications from a cell comprising at least one base station, theuser equipment (UE) comprising: a receiver configured to receive fromthe base station both a cell specific radio resource control (RRC)configuration comprising a cell specific resource offset parameter for aPUCCH carrying a HARQ-ACK, and a UE specific RRC configurationcomprising a UE specific RS base sequence parameter and an UE specificresource offset parameter for the PUCCH carrying the HARQ-ACK; and atransmitter configured to transmit the PUCCH carrying the HARQ-ACK whichis generated based on either the cell specific RRC configuration or theUE specific RRC configuration, wherein a resource index number for thePUCCH, n_(PUCCH) ⁽¹⁾, is determined by the following equation:n _(PUCCH) ⁽¹⁾ =n _(CCE) +N _(PUCCH) ⁽¹⁾, where n_(CCE) is a number ofthe smallest channel control element (CCE) used for transmission of acorresponding downlink control information scheduling a PDSCH for whichthe PUCCH carries the HARQ-ACK, and N_(PUCCH) ⁽¹⁾ is the UE specificresource offset parameter depending on the applicability in case the UEspecific RRC configuration is applicable to the user equipment;otherwise N_(PUCCH) ⁽¹⁾ is the cell specific resource offset parameter.2. The user equipment as set forth in claim 1, wherein the UE specificRRC configuration contains an indication parameter indicating whetherthe UE specific RRC configuration or the cell specific RRC configurationis applicable to the user equipment.
 3. The user equipment as set forthin claim 1, wherein the UE specific RRC configuration is applicable tothe user equipment in case that the user equipment receives thecorresponding downlink control information carried in an enhanced-PDCCH;the cell specific RRC configuration is applicable to the user equipmentin case that the user equipment receives the corresponding downlinkcontrol information carried in a PDCCH region.
 4. The user equipment asset forth in claim 1, wherein in case that the user equipment interfereswith another user equipment connected to another cell above a specifiedthreshold, the identical UE specific RS base sequence and UE specificresource offset parameters are transmitted to the user equipments. 5.The user equipment as set forth in claim 1, wherein the UE specificresource offset parameter is selected from at least one of a number ofCSI-RS configuration numbers associated with non-zero CSI-RStransmission power.
 6. The user equipment as set forth in claim 1,wherein the reference signal (RS) is generated by a sequence groupnumber u derived from the following equation:u=(f _(gh)(n _(s))+f _(ss))mod 30, where f_(gh)(n_(s)) is a grouphopping pattern and f_(ss) is a sequence-shift pattern.
 7. The userequipment as set forth in claim 6, wherein f_(ss) is equal to asequence-shift pattern for the PUCCH f_(ss) ^(PUCCH), the sequence-shiftpattern for the PUCCH f_(ss) ^(PUCCH) is determined by the followingequation:f _(ss) ^(PUCCH)=(N)mod 30, wherein N is the UE specific RS basesequence parameter in case the UE specific RRC configuration isapplicable to the user equipment; otherwise N is a cell identificationof the cell.
 8. For use in a wireless communications network comprisinga plurality of cell including at least one base station, each one of thebase stations capable of wireless communications with a plurality ofuser equipments, the base station comprising: a transmitter configuredto transmit to the user equipment both a cell specific radio resourcecontrol (RRC) configuration comprising a cell specific resource offsetparameter for a PUCCH carrying a HARQ-ACK, and a UE specific RRCconfiguration comprising a UE specific RS base sequence parameter and anUE specific resource offset parameter for the PUCCH carrying theHARQ-ACK; and a receiver configured to receive the PUCCH carrying theHARQ-ACK which is generated based on either the cell specific RRCconfiguration or the UE specific RRC configuration, wherein a resourceindex number for the PUCCH, n_(PUCCH) ⁽¹⁾, is determined by thefollowing equation:n _(PUCCH) ⁽¹⁾ =n _(CCE) +N _(PUCCH) ⁽¹⁾ where n_(CCE) is a number ofthe smallest channel control element (CCE) used for transmission of acorresponding downlink control information scheduling a PDSCH for whichthe PUCCH carries the HARQ-ACK, and N_(PUCCH) ⁽¹⁾ is the UE specificresource offset parameter in case the UE specific RRC configuration isapplicable to the user equipment; otherwise N_(PUCCH) ⁽¹⁾ is the cellspecific resource offset parameter.
 9. The base station as set forth inclaim 8, wherein the UE specific RRC configuration contains anindication parameter indicating whether the UE specific RRCconfiguration or the cell specific RRC configuration is applicable tothe user equipment.
 10. The base station as set forth in claim 8,wherein the UE specific RRC configuration is applicable to the userequipment in case that the user equipment receives the correspondingdownlink control information carried in an enhanced-PDCCH; the cellspecific RRC configuration is applicable to the user equipment in casethat the user equipment receives the corresponding downlink controlinformation carried in a PDCCH region.
 11. The base station as set forthin claim 8, wherein in case that the user equipment interferes withanother user equipment connected to another cell above a specifiedthreshold, the identical UE specific RS base sequence and UE specificresource offset parameters are transmitted to the user equipments. 12.The base station as set forth in claim 8, wherein the UE specificresource offset parameter is selected from at least one of a number ofCSI-RS configuration numbers associated with non-zero CSI-RStransmission power.
 13. The base station as set forth in claim 8,wherein the reference signal (RS) is generated by a sequence groupnumber u derived from the following equation:u=(f _(gh)(n _(s))+f _(ss))mod 30, where f_(gh)(n_(s)) is a grouphopping pattern and f_(ss) is a sequence-shift pattern.
 14. The basestation as set forth in claim 8, wherein f_(ss) is equal to asequence-shift pattern for the PUCCH f_(ss) ^(PUCCH), the sequence-shiftpattern for the PUCCH f_(ss) ^(PUCCH) is determined by the followingequation:f _(ss) ^(PUCCH)=(N)mod 30, wherein N is the UE specific RS basesequence parameter in case the UE specific RRC configuration isapplicable to the user equipment; otherwise N is a cell identificationof the cell.
 15. For use in a wireless communications network, a methodfor interference mitigation, the method comprising: transmitting to auser equipment both a cell specific radio resource control (RRC)configuration comprising a cell specific resource offset parameter for aPUCCH carrying a HARQ-ACK, and a specific RRC configuration comprising aUE specific RS base sequence parameter and an UE specific resourceoffset parameter for the PUCCH carrying the HARQ-ACK; and receiving thePUCCH which is generated based on either the cell specific RRCconfiguration or the UE specific RRC configuration, wherein a resourceindex number for the PUCCH, n_(PUCCH) ⁽¹⁾, is determined by thefollowing equation:n _(PUCCH) ⁽¹⁾ =n _(CCE) +N _(PUCCH) ⁽¹⁾ where n_(CCE) is a number ofthe smallest channel control element (CCE) used for transmission of acorresponding downlink control information scheduling a PDSCH for whichthe PUCCH carries the HARQ-ACK, and N_(PUCCH) ⁽¹⁾ is the UE specificresource offset parameter in case the UE specific RRC configuration isapplicable to the user equipment; otherwise N_(PUCCH) ⁽¹⁾ is the cellspecific resource offset parameter.
 16. The method as set forth in claim15, wherein the UE specific RRC configuration contains an indicationparameter indicating whether the UE specific RRC configuration or thecell specific RRC configuration is applicable to the user equipment. 17.The method as set forth in claim 15, wherein the UE specific RRCconfiguration is applicable to the user equipment in case that the userequipment receives the corresponding downlink control informationcarried in enhanced-PDCCH; the cell specific RRC configuration isapplicable to the user equipment in case that the user equipmentreceives the corresponding downlink control information carried in aPDCCH region.
 18. The method as set forth in claim 15, wherein in casethat the user equipment interferes with another user equipment connectedto another cell above a specified threshold, the identical UE specificRS base sequence and UE specific resource offset parameters aretransmitted to the user equipments.
 19. The method as set forth in claim15, wherein the UE specific resource offset parameter is selected fromat least one of a number of CSI-RS configuration numbers associated withnon-zero CSI-RS transmission power.
 20. The method as set forth in claim15, wherein the reference signal (RS) is generated by a sequence groupnumber u derived from the following equation:u=(f _(gh)(n _(s))+f _(ss))mod 30, where f_(gh)(n_(s)) is a grouphopping pattern and f_(ss) is a sequence-shift pattern.
 21. The methodas set forth in claim 15, wherein f_(ss) is equal to a sequence-shiftpattern for the PUCCH f_(ss) ^(PUCCH), the sequence-shift pattern forthe PUCCH f_(ss) ^(PUCCH) is determined by the following equation:f _(ss) ^(PUCCH)=(N)mod 30, wherein N is the UE specific RS basesequence parameter in case the UE specific RRC configuration isapplicable to the user equipment; otherwise N is a cell identificationof the cell.